An organic electroluminescence device (referred to below as “organic EL device”) is provided with an organic electroluminescence layer (referred to below as “organic EL layer”) between an anode and cathode. Although the organic EL device emits light according to the amount of current flowing in the device, it is known that water or oxygen badly affects the organic EL device which degrades light emitting characteristics.
As a result, an organic electroluminescence display device (below referred to as “organic EL display device”) formed with pixels using an organic EL device is usually provided with a structure in which a pixel region is sealed with a sealing material. Although various structures have been examined for the sealing structure of an organic EL display device, for example, a structure is known in which a sealing substrate is bonded facing a substrate provided with a pixel using an organic EL device.
The structure in which a substrate formed with an organic EL device is bonded with sealing substrate is similar to a liquid crystal display device in which a liquid crystal material is held between a pair of substrates. However, because an organic EL display device an image using the light emitted by an organic EL device, a back light is not required unlike in a liquid crystal display device and in principle it is possible to achieve a thin display panel. Furthermore, it is thought that it is possible to also realize a sheet shaped display panel (sheet display) by applying a resin film to a substrate formed with a device or a sealing substrate.
Even in the vase where a resin film is used as a substrate in an organic EL display device, a sealing structure is necessary in order to prevent degradation due to the effects of water on the organic EL device. Generally, a resin film has the property to allow water to pass through and also includes the property whereby water is easily included and once included is reradiated.
As a result, arranging a barrier layer on a resin film used as a substrate in an organic EL display device in order to prevent the infiltration of water has been examined. For example, in Japanese Laid Open Patent No. 2011-227369, an image display device is disclosed provided with a first substrate comprised from a curved transparent substrate and a resin film formed with a thin film transistor adhered to an upper layer of the first substrate, wherein the barrier layer is comprised form an inorganic layer which covers the surface, rear surface and side surface of the resin film.
However, since the structure of the end surface of the resin film has not been considered in the display device described in the patent document 1, the problem whereby barrier properties at the end surface are insufficient still remains. In addition, because a process for forming a double resin film layer is necessary, an increase in component costs and manufacturing costs is considered a problem.
When the end surface of a resin film is cut perpendicularly, it is possible that the end surface is not sufficiently covered by a barrier layer. In the case where a barrier layer is a thin film comprised from an inorganic material such as a silicon oxide layer or silicon nitride layer, the barrier layer is formed using a sputtering method or plasma CVD method. However, this type of thin film formed from an inorganic material is not always formed at a uniform thickness at the end surface perpendicular with the surface of the resin film.
In the case where the film thickness of the barrier layer at the end surface of the resin film is insufficient, water or oxygen enters the device from that part. On the other hand, when attempting to make the film thickness of the barrier layer at the end surface of the resin film thicker, the film thickness of the surface side the resin film increases, the flexibility of the film is lost and there is a danger that cracks appear in the barrier film when the resin film is bent.
Therefore, one embodiment of the present invention aims to provide a display device with a high level of reliability which prevents the infiltration of water or oxygen from the end surface of a substrate in a display device which uses a resin film as the substrate.